Definition of "nitrobacterium" []

• Any of various soil bacteria that take part in the nitrogen cycle, oxidizing ammonium compounds into nitrites or nitrites into nitrates. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.